Imaging Sand Distribution From Acoustic Impedance Imaging Sand Distribution From Acoustic Impedance
Suphan Buri Basin, Suphan Buri Basin,
Central Thailand.Central Thailand.
Imaging Sand Distribution From Acoustic Impedance Imaging Sand Distribution From Acoustic Impedance
Suphan Buri Basin, Suphan Buri Basin,
Central Thailand.Central Thailand.
Dept. Petroleum Geoscience, Universiti Brunei Darussalam.
PTT Exploration and Production PCL., Bangkok, Thailand.
Ronghe, S., and Surarat, K.1 2
1
2
CONTENTS
• Study objectives• Location and geology• Wireline analysis• Well to seismic correlation• Seismic attribute analysis• Inverse modeling• Results and interpretation• Conclusions• Acknowledgements
STUDY OBJECTIVES
• To determine the potential of wireline and seismic as a discriminator of formation lithology / fluid.
• To apply the seismic inversion to image depositional succession
STUDY LOCATION STUDY LOCATION STUDY LOCATION STUDY LOCATION
PhitsanulokBasin
Sing BuriBasin
KamphaengSaen Basin
Ayuthaya Basin
Sala Daeng Basin
THAILAND
BANGKOK
Three Pagodas
Fault Zone
Mae Ping Fault Zone
30 km
N
Adapted from O’Leary and Hill (1989)
STUDY AREA
Suphan Buri Basin
Oli
goce
neM
ioce
neP
lioc
ene
- R
ecen
t
Low
erM
idU
pper
Age Unit
U
A
B
C
D
E
C1
C2
Pre Tertiary
C3
C4
D7
D1
D6
D5
D4
D3
D21000 -
U
1500 -
2000 -
500 -
m
Alluvial - Fluvial
Depositional system
Fluvio- lacustrine
Lacustrine
Early basin fillAlluvial - lacustrine
Lithology
Sands, gravels, siltstone & mudstone,fluvial origin
Fluvio-lacustrine sandstone, siltstoneinterbedded with mudstone.
Fluvial channel sandstone andconglomeratic sandstone.
Intercalated sandstone, siltstone & mudstone.Lacustrine system with fluvial influence.
Mudstone with minor siltstone.
Conglomerate, sandstone interbeddedwith siltstone and minor mudstone.
Basement complex: clastics,carbonate rocks or metasediments.
Petroleum system
Reservoirs
Source andReservoirs
Source andReservoirs
Source
Source
Depth
Schematic stratigraphic sequence, Suphan Buri BasinSchematic stratigraphic sequence, Suphan Buri BasinSchematic stratigraphic sequence, Suphan Buri BasinSchematic stratigraphic sequence, Suphan Buri Basin
Adapted from Intharawijitr (1993)
Time(ms)
1 Km
N
Horizon D3
UT1-3
UT1-7
UT1-3/D
1
UT1-7/D2
560
630
700
770
840
910
980
1059
Time structuremap
Area = 37 sq. km.
TWT STRUCTURAL MAPTWT STRUCTURAL MAPTWT STRUCTURAL MAPTWT STRUCTURAL MAP
GR GR AIAI
Well UT1-7 Well UT1-3
mTVD
mTVD
Sub-unit D1
Sub-unit D2
Sub-unit D3
Sub-unit D5
Sub-unit D6
Sub-unit D4 OWCOWC
Wireline cross-plotsBelow OWC
Wireline cross-plotsAbove OWC
CONTENTS
• Study objectives• Location and geology• Wireline analysis• Well to seismic correlation• Seismic attribute analysis• Inverse modeling• Results and interpretation• Conclusions• Acknowledgements
GRAI
Shaly-sand
Sand
Shale
Wireline cross-plot: Wireline cross-plot: BelowBelow OWC OWCWireline cross-plot: Wireline cross-plot: BelowBelow OWC OWC
Low
High
Impedance (g/cc * m/s)
Gam
ma
ray
(A
PI)
-13UT
GRLLD
Wireline cross-plot: Wireline cross-plot: BelowBelow OWC OWCWireline cross-plot: Wireline cross-plot: BelowBelow OWC OWC
Gam
ma
ray
(A
PI)
Resistivity (ohm / m)
-13UT
Shaly-sand
Sand
ShaleGRAI
Wireline cross-plot: Wireline cross-plot: AboveAbove OWC OWCWireline cross-plot: Wireline cross-plot: AboveAbove OWC OWC
Low
High
Impedance (g/cc * m/s)
Gam
ma
ray
(A
PI)
-17
GRLLD
Wireline cross-plot: Wireline cross-plot: AboveAbove OWC OWCWireline cross-plot: Wireline cross-plot: AboveAbove OWC OWC
Gam
ma
ray
(A
PI)
Resistivity (ohm / m)
-17
WaveletWavelet
SyntheticSyntheticSeismicSeismic SyntheticSyntheticImpedance (g/cc*m/s)Impedance (g/cc*m/s)
WELL TO SEISMIC CORREL WELL TO SEISMIC CORRELATIONATION
WELL TO SEISMIC CORREL WELL TO SEISMIC CORRELATIONATION
CONTENTS
• Study objectives• Location and geology• Wireline analysis• Well to seismic correlation• Seismic attribute analysis• Inverse modeling• Results and interpretation• Conclusions• Acknowledgements
GR GR AIAI
Well UT1-7 Well UT1-3
mTVD
mTVD
Sub-unit D1
Sub-unit D2
Sub-unit D3
Sub-unit D5
Sub-unit D6
Sub-unit D4 OWCOWC
Wireline cross-plotsBelow OWC
Wireline cross-plotsAbove OWC
CONTENTS
• Study objectives• Location and geology• Wireline analysis• Well to seismic correlation• Seismic attribute analysis• Inverse modeling• Results and interpretation• Conclusions• Acknowledgements
INVERSE MODELLING FLOWCHARTINVERSE MODELLING FLOWCHART
Final AI result
Trace merge
Impedance(mid frequency)
Impedance(low frequency)
CSSI AI model
Solid earth modelAI
ConstraintsAI
Interpolation
WAVELETS SEISMIC LOGS TOPS HORIZONS FAULTS
AI log
ConstraintsTrend
IMPEDANCE TREND AND CONSTRAINTSIMPEDANCE TREND AND CONSTRAINTSIMPEDANCE TREND AND CONSTRAINTSIMPEDANCE TREND AND CONSTRAINTS
Well SK-1
20m
12m
18m
INVERSE MODELING RESULTINVERSE MODELING RESULTINVERSE MODELING RESULTINVERSE MODELING RESULT
Impedance(g/cc * m/s)
10000
10500
11000
11500
12000
12500
13000
13500
SAND
Sub-unit D6
Maximumimpedancedistribution
1 Km
N
UT1-3
UT1-7
UT1-3/D
1
UT1-7/D2
Sub-unit D5
Maximumimpedancedistribution
1 Km
N
Impedance(g/cc * m/s)
13500
10000
12000
12500
13000
10500
11500
11000
9500
SAND
UT1-3
UT1-7
UT1-3/D
1
UT1-7/D2
Impedance(g/cc * m/s)
9500
9000
10000
10500
11000
11500
12000
12500
13000
SAND
Sub-unit D4
Maximumimpedancedistribution
1 Km
N
UT1-3
UT1-7
UT1-3/D
1
UT1-7/D2
Sub-unit D3
Maximumimpedancedistribution
1 Km
N
Impedance(g/cc * m/s)
12500
13000
12000
11500
11000
10500
10000
9500
9000
SAND
UT1-3
UT1-7
UT1-3/D
1
UT1-7/D2
Generalized rift structure and sedimentation patternsGeneralized rift structure and sedimentation patternsGeneralized rift structure and sedimentation patternsGeneralized rift structure and sedimentation patterns
DELTAIC / FLUVIALSandstone + mudstone
Fan in footwall transfer zone
ALLUVIAL FAN / FAN DELTAConglomerate + sandstone
(Modified from Leeder and Gawthorpe 1987)
1 Km
N
FS
DL
Sub-unit D6
ImpedanceInterpretation FS
FC
FS
DL
Sub-unit D5
ImpedanceInterpretation
1 Km
N
LEGEND
FS
DL
Shale
Sand
Transportdirection
Fan / slump
Delta lobe
Feeder canyonFC
BF
C
DL
FS
Sub-unit D4
ImpedanceInterpretation
1 Km
N
LEGEND
FS
DL
Shale
Sand
Transportdirection
Fan / slump
Delta lobe
Channel
Basinfloor fan
C
BF
BF
C
DL
FS
FC
Sub-unit D3
ImpedanceInterpretation
1 Km
N
Axial delta lobe
Basinfloor fans
Axial channel
Max
imum
dis
plac
emen
t
Remnantrelay ramp
Max
imum
dis
plac
emen
t
Min
imum
dis
pl.
Fault linkage
Feeder canyons
N
1.50
Km
Fan or slump
SUMMARY GEOLOGICAL MODEL OF THE STUDY AREASUMMARY GEOLOGICAL MODEL OF THE STUDY AREASUMMARY GEOLOGICAL MODEL OF THE STUDY AREASUMMARY GEOLOGICAL MODEL OF THE STUDY AREA
CONCLUSIONS (1)
• Wireline impedance and seismic attributes responded primarily to lithology.
• Inverse modeling resulted in good comparison between wireline impedance and adjacent derived impedance traces, and enabled vertical sand resolution of about 12 m. • Maximum impedance extractions imaged two styles of sand distribution: axial and boundary fault induced deposits.
CONCLUSIONS (2)
• Axial deposits (delta lobes, channels and basinfloor fans) prograded from south to north downdip into the basin.
• Boundary fault induced deposits (fans / slumps and feeder canyons) showed two component pathways:
•Fans / slumps were transported perpendicular to the fault.•Feeder canyons transported sediment downslope to the NE.
• The basin architecture and sedimentation patterns agree with published general models of rift geology.
ACKNOWLEDGEMENTS
• PTT Exploration and Production Public Co. Ltd. for data & permission to present the results.
• Jason Geosystems and Landmark Graphic Corp. for software donation to the Department of Petroleum Geoscience, UBD.
• Jason Geosystems for technical support and review of this study.
PRESENTATION OVERVIEW
Acoustic impedance is used to map the Acoustic impedance is used to map the
locations and shapes of sand bodies locations and shapes of sand bodies
deposited within a producing fluvio-deposited within a producing fluvio-
lacustrine interval of a continental half lacustrine interval of a continental half
graben basin.graben basin.
Acoustic impedance is used to map the Acoustic impedance is used to map the
locations and shapes of sand bodies locations and shapes of sand bodies
deposited within a producing fluvio-deposited within a producing fluvio-
lacustrine interval of a continental half lacustrine interval of a continental half
graben basin.graben basin.